This invention relates in general to telephone systems and in particular to a method and apparatus for providing an intercept message.
The use of intercept messages to explain why a call cannot be completed is commonplace in telephone systems. Such intercept messages are typically initiated whenever an outgoing call cannot be completed for various reasons, such as the called number being out of service or not being a working number, so that the person who made the call receives a recorded audio message advising that his call was not completed as dialed.
Intercept messages according to the known prior art are delivered at the point of terminus of switching progress, generally the end office or intermediate switching office where an intercept condition such as congestion, delay or change has occurred. The particular audio intercept message is returned along a trunk circuit to the originating office, so that the calling party can receive the message.
In the case of calls placed on long haul trunk circuits between distant locations, or between different countries, the conventional return of audio intercept messages creates a number of undesirable effects upon the telephone network and the calling public. Since the trunk circuit must be held for sufficient time to return the audio intercept message, typically forty seconds or more, telephone switching equipment and trunk lines are tied up which could otherwise be utilized for improved customer service. Where intercept messages are returned between countries having different languages, a recorded intercept message in the language of the terminating country (from which the message is returned) may have no meaning to a person in an originating country of a different national language. A similar problem can arise where an intercept message is returned to a locality which has a significant bilingual population. An English-language intercept message returned from an end office will be meaningless to an originating-office telephone subscriber who speaks only Spanish. While the call-originating country could be equipped with apparatus for delivering prerecorded intercept messges in a number of different languages, the cost and complication of such duplication of equipment is evident.
Accordingly, it is an object of the present invention to provide an improved method and apparatus for delivering intercept messages.
It is another object of the present invention to provide an intercept message method and apparatus which reduces trunk holding time.
It is still another object of the present invention to provide an intercept message method and apparatus for delivering the intercept message in a language which is native to the originating telephone of the call.
It is still a further object of the present invention to provide a method and apparatus delivering intercept messages which is compatible with the existing North American telephone network and other telephone networks throughout the world and which will require a minimum of retrofitting of additional equipment to, or modification of generic programs of, existing central offices.
It is still a further object of the present invention to provide apparatus for the revertive intercept arrangement of the present invention which will also deliver intercept messages in a conventional manner when one of the central offices handling the call lacks the apparatus of the present invention.
It is still a further object of the present invention to provide a method of local delivery of intercept messages compatible with the existing format of common channel interoffice signaling (CCIS) message units.
That the present invention meets the objects of the invention as stated above will be apparent from the description to follow.
Stated in general terms, the intercept system of the present invention delivers intercept messages which are originated at the originating office, rather than at the destination office or at some intermediate switching location. When a message intercept condition occurs at the destination office or some other location remote of the originating office, an intercept message signal is returned to the originating office. This intercept message signal is used to actuate suitable announcement message apparatus associated with the originating office, so as to deliver an appropriate audio message to the calling party. A suitable signal for selecting an appropriate intercept message can typically be returned to the calling location in a few seconds or less, so that the trunk circuit can thereafter be released for other service.
Since the intercept announcement message is provided locally, the message can readily be delivered in the native language and idiom in response to a particular returned intercept signal. The originating office is equipped to forward an acknowledgement signal to the terminating office indicating that the originating office is properly equipped for local origination of intercept signals, whereupon the trunk circuit can be released; in the absence of such a returned confirmation signal within a predetermined time, the intercept message audio announcement can be returned over the trunk circuit to the originating office in the conventional manner, thus assuring compatibility of the present invention with originating offices that are not yet equipped with such apparatus.